1. Field of the Invention
The present invention relates, generally, to a control panel assembly, and more particularly to a control panel assembly with a moveable illuminating button and a method of making the same.
2. Description of the Related Art
Many devices include control panels with stylized displays, dials, knobs and more. Control panel assemblies can also include buttons as a means for controlling associated systems. For instance, vehicle control panel assemblies can include buttons used to control the vehicle air conditioner, stereo, and more. When light levels are low, however, the user may not be able to properly see the control buttons.
Partially in response to this need, control panel assemblies have been designed which include light sources for backlighting the buttons. Incandescent light bulbs, LEDs, and the like are supported near the back surface of the buttons to backlight the buttons and allow the user to see the controls. However, the light sources of these control panel assemblies typically generate undesirable heat when illuminated, can be sensitive to shock, and generally disperse light unevenly. Also, these control panel assemblies often require light pipes to direct light in a desired path, thereby increasing assembly time and cost. Furthermore, these light sources and the light pipes take up a relatively large amount of space. Therefore, there is an ongoing need for an improved means for illuminating control panel assemblies.
Some control panel assemblies include buttons that are backlit with electroluminescent (EL) film. EL film is a known material having a phosphorous layer that emits light when a voltage is applied. For instance, U.S. Pat. No. 6,148,075 to Inubushi et al. discloses such a control panel assembly for a cellular telephone. The control panel assembly includes a button array and an EL film for backlighting the buttons. The EL film is disposed behind the button array such that light emitted from the EL film backlights the button array.
Although the Inubushi et al. control panel assembly generally works for its intended purpose, some disadvantages remain. For instance, in some applications, especially in vehicle control panel assemblies, buttons with a relatively long stroke are preferred. However, the buttons of the Inubushi et al. device are connected together, and this arrangement can limit the amount of travel of the button. Moreover, because the EL film is disposed behind the buttons, light emitted from the EL film may not be strong enough to be adequately seen through the buttons.
Therefore, there remains an ongoing need for an improved control panel assembly with buttons that includes EL film for illuminating the controls. Specifically, there is a need for such a control panel assembly with improved manufacturability and improved display characteristics.